The Properties of Matter Section 2 Physical Properties

Can be observed or measured without changing the substance’s identity Can be observed or measured without changing the substance’s identity Color, odor, shape & volume are physical properties Color, odor, shape & volume are physical properties

Useful Physical Properties in Science Thermal conductivity – how fast a substance transfers heat Thermal conductivity – how fast a substance transfers heat Solubility – ability of one substance to dissolve in another substance Solubility – ability of one substance to dissolve in another substance

Useful Physical Properties in Science (con’t.) State – physical form in which a substance exists State – physical form in which a substance exists Ductility – ability of a substance to be pulled into a wire Ductility – ability of a substance to be pulled into a wire

Useful Physical Properties in Science (con’t.) Malleability – ability of a substance to be pounded or rolled into thin sheets Malleability – ability of a substance to be pounded or rolled into thin sheets Density – the amount of mass per unit volume Density – the amount of mass per unit volume

Density Describes the relationship between the amount of mass and the volume of a substance Describes the relationship between the amount of mass and the volume of a substance Every pure substance has its own unique density. Every pure substance has its own unique density. Can be used to identify unknown substances Can be used to identify unknown substances

Solving for Density Measure the object’s mass. Measure the object’s mass. Measure the object’s volume. Measure the object’s volume. Use the formula density = mass Use the formula density = massvolume

Density Units Combination of the mass unit and volume unit Combination of the mass unit and volume unit Mass is usually measured in grams or kilograms. Mass is usually measured in grams or kilograms. Volume is usually measured in milliliters or liters. Volume is usually measured in milliliters or liters. Solid volume is measured in cubic centimeters. Solid volume is measured in cubic centimeters. Density units are written g/mL and read “grams per milliliter.” Density units are written g/mL and read “grams per milliliter.”

Sample Density Problem What is the density of an object whose mass is 25 g and whose volume is 10 cm 3 ? What is the density of an object whose mass is 25 g and whose volume is 10 cm 3 ? Write the formula: D = m Write the formula: D = m V V Substitute the values: D = 25g Substitute the values: D = 25g 10 cm 10 cm Solve: D = 2.5 g/cm 3 Solve: D = 2.5 g/cm 3

Other Useful Formulas To solve for mass: m = D x V To solve for mass: m = D x V To solve for volume: V = m To solve for volume: V = mD